The present invention relates to a reduced form of Coenzyme Q also known as Ubiquinol in a gelatin capsule, preferably a soft gelatin capsule, in oral administrable form. Compositons according to the present invention exhibit unexpectedly high bioavailability of the reduced (active) form of Coenzyme Q.
The use of dietary supplements has become an increasingly common approach to obtaining and maintaining good health. One of these dietary supplements, Coenzyme Q, is a vitamin-like substance which is used to treat congestive heart failure and other cardiac problems. Coenzyme Q is the best known of a group of lipophilic quinones which have the capacity to transfer reducing equivalents or electrons within a lipid phase of cellular membranes. Other quinones of this general lipophilic type found in cells are of diverse species. A few include, for example, rhodoquinone, menaquinone, plastoquinone, chlorobiumquinone, thermoplasmaquinone and phylloquinone. See, Collins, 1985, Methods in Micobiol. 18: 329-360. It is postulated that the diene dione chemical structure of these compounds provides a platform for the transfer of one or two electrons and associated protons within the lipid bilayers of cells or to and from hydrophobic redox centers in proteins.
Reduced benzoquinones in general are effective reductants for oxygen or lipid radicals. Early studies showed that reduced coenzyme Q is an effective antioxidant. See, Mellors and Tappel, 1996, J. Biol. Chem., 241: 4353-4356. Reduced coenzyme Q now appears to function as part of a complex chain of antioxidant activity. The most important role of coenzyme Q can be in reduction of radicals of xcex1-tocopherol and ascorbate formed when these antioxidants are oxidized by oxygen or carboxyl radicals. There are no enzymes for direct reduction of tocopheryl radical or external ascorbate radical, but there are enzymes in all membranes which can reduce coenzyme Q and the reduced coenzyme Q can reduce the tocopheryl or ascorbate radicals to restore tocopherol or ascorbate. Without the support of enzymes to reduce coenzyme Q, the reduced coenzyme Q would not be a very effective antioxidant because the semiquinone formed by interaction with lipid or oxygen radicals is readily autooxidized with formation of a superoxide radical.
The enzymes involved in coenzyme Q reduction are the primary dehydrogenases for succinate. NADH or other substrates in mitochondria, the NADH cytochorome b5 reductase in endo and plasma membranes and DT diaphorase or NADPH dehydrogenase enzymes primarily located in the cytosol. Villalbe, et al., Proc. Natl. Acad. Sci. 92:4887-4891 (1995); Beyer, et al., Molec. Aspects Med,. 18(S): 15-23 (1997); and Kishi, et al., Molec. Aspects Med,. 18(S): 71-77 (1997).
Coenzyme Q in endo membranes or plasma membranes is extensively in the reduced form, most of the coenzyme Q in total rat and human tissue is in the reduced form and most of the coenzyme Q in serum is in the reduced state. See, Takahashi, et al., Lipids, 28: 803-809, (1993); xc3x84berg, et al., Arch. Biochem. Biophys., 295: 230-234 (1992); and Yamamoto and Yamashita, Molec. Aspects Med., 18 (S) (1997).
Studies performed to date have not focused on the differential uptake and bioavailability of one form of coenzyme Q versus another form of coenzyme Q. Nor has the art recognized the desirability of using ubiquinol as an active pharmacological agent to enhance the bioavailability of coenzyme Q from oral formulations.
It is an object of the invention to provide storage stable compositions for administering a reduced form of coenzyme Q.
It is an additional object of the invention to provide a method for enhancing the bioavailability of coenzyme Q to patients by administering effective amounts of coenzyme Q in a reduced form.
It is also an object of the present invention to provide an economical means for making ubiquinol-containing compositions from the more readily available and economical coenzyme Q10 (Ubiquionone).
These and/or other objects of the present invention may be readily gleaned from the detailed description of the invention which follows.
The present invention relates to novel storage stable compositions in oral dosage form comprising effective amounts of ubiquinol, a reduced form of coenzyme Q, in combination with an amount of a lipid soluble reducing agent effective to maintain ubiquinol in its reduced state when preferably formulated in a soft gel capsule. Compositions according to tifpresent invention may be used for treatment of heart ailments and diseases such as congestive heart failure, mitochochondrial disorders, including mitochondrial encephalomyopathy, lactic acidosis, and strokelike symptoms, Keams-Sayre syndrome and Alper""s disease. In addition, the use of ubiquinol to aid in the prevention of reperfusion injury of the heart is another potential use of the present invention.
It is an unexpected result that formulations comprising ubiquinol in soft gel capsules, when administered to patients, exhibit a bioavailability of ubiquinol which is substantially greater than when ubiquinone is administered in oral dosage form, preferably soft gel capsule form. Thus, the present compositions also represent a method for substantially enhancing the bioavailability of Coenzyme Q10 in the patient""s blood stream of an orally administrable form of ubiquinol.
The term xe2x80x9ccoenzyme Qxe2x80x9d or xe2x80x9cubiquinonexe2x80x9d is used throughout the present specification to describe a group of lipid soluble benzoquinones involved in electron transport in mitochondrial preparations, i.e., in the oxidation of succinate or reduced nicotine adenine dinucleotide (NADH) via the cytochrome system. According to the existing dual system of nomenclature, the compounds can be described as: coenzyme Qn where n is 1-12 or ubiquinone (x) in which x designates the total number of carbon atoms in rthe side chain and can be any multiple of 5. Differences in properties are due to to the difference in the chain length. The preferred ubiquinone for use in the present invention is the reduced form of coenzyme Q10 or ubiquinol. 
The term xe2x80x9cubiquinolxe2x80x9d is used throughout the specification to describe the reduced form of coenzyme Q which is used as the active ubiquinone in compositions according to the present invention. In ubiquinol, the quinone ring of coenzyme Q is reduced such that the structure of the compound appears as set forth below. In ubiquinol, n is preferably 10 and is derived from coenzyme Q10. The amount of ubiquinol which is included in compositions according to the present invention ranges from about 0.1% to about 50% by weight of the final composition which is encapsulated in a soft gelatin capsule, more preferably about 0.5% to about 10% by weight, even more preferably about 1% to about 5% by weight. The amount of ubiquinol which is included in compositions to be encapsulated ranges from about 0.1 to about 10.0 times, more preferably about 1 to about 3 times the amount (in weight percent) of the lipid soluble reducing agent which is included in compositions according to the present invention. 
The terms xe2x80x9creducing agentxe2x80x9d and xe2x80x9clipid soluble reducing agentxe2x80x9d are used throughout the specification to describe pharmaceutically acceptable reducing agents which are added to the compositions according to the present invention in effective amounts to convert ubiquinone to ubiquinol during manufacturing and in preferred embodiments, to substantially reduce oxidation of ubiquinol to ubiquinone (Coenzyme Q) during manufacturing and/or storage of the oral dosage form of compositions according to the present invention. Preferred lipid soluble reducing agents include any reducing agent which is lipid or fat soluble and is capable of providing the requisite reducing activity to stabilize ubiquinol for storage, preferred lipid soluble reducing agents include, for example, xcex1-tocopherol (vitamin E), tocopherol esters, ascorbate esters such as ascorbyl palmitate, among others, xcex2-carotene, retinol (Vitamin A), retinoic acid, retinoic acid esters, retinol acetate, retinal and related reducing agents, preferably those which may also be used as additives in dietary supplements. Preferred lipid soluble reducing agents are those which are also soluble in the solvents (such as a polyhydric alcohol glycerine or propylene glycol) which are used to prepare hydrosoluble compositions comprising a reducing agent and ubiquinol. A lipid soluble reducing agent for use in the present invention comprises about 0.05% to about 25% by weight of the composition which is included in soft gelatin capsules, more preferably about 1% to about 15% by weight. The ratio of reducing agent to ubiquinol in compositions according to the present invention generally ranges from about 0.1:1 to about 10:1, more preferably about about 1:5 to about 5:1, more preferably about 1:1 to about 3:1. In embodiments according to the present invention which rely on an in situ preparation of ubiquinol from ubiquinone, the amount of reducing agent which is used in the reduction is preferably an excess of that amount required for the reduction reaction. The remaining reducing agent may then be incorporated into the final formulations in order to promote the storage stability of the ubiquinol.
While not being limited by way of theory, it is believed that effective concentrations of reducing agents convert substantially all ubiquinone to ubiquinol during manufacturing in an efficient method for preparing ubiquinol. In other embodiments, effective concentrations of reducing agents also prevent ubiquinol from being oxidized to ubiquinone, or alternatively reduce any ubiquinone which has been oxidized from ubiquinol during storage of the compositions according to the present invention.
The term xe2x80x9csolventxe2x80x9d is used throughout the specification to describe a liquid into which is at least partially solubilized the ubiquinol and reducing agent, either alone or preferably in combination with a surfactant as otherwise described herein, is added. Solvents for use in the present invention include any hydrophilic solvent which is pharmaceutically acceptable and which can be used as a solvent, which alone, or in combination with surfacants as otherwise described herein, dissolves ubiquinol and the reducing agent. Preferred solvents for use in the present invention include ethanol and xe2x80x9cpolyhydric alcoholsxe2x80x9d a term which is used throughout the present invention to describe any one or more pharmaceutically compatible polyhydric alcohol compounds which are used to solubilize ubiquinol and the reducing agent used in compositions according to the present invention. Polyhydric alcohols which may be used in the present invention include, for example, glycerine (glycerol), propylene glycol and mixtures, thereof. The amount of solvent which is used in the present compositions ranges from about 0.25% to about 25% by weight, preferably about 1% to about 15% by weight.
The term xe2x80x9csurfactantxe2x80x9d or xe2x80x9cemulslifierxe2x80x9d is used interchangeably to describe preferred additives to compositions according to the present invention. Surfactants are solubilizers which are used to promote the solubility of the ubiquinol and the reducing agent in the polyhydric alcohol. These may be used alone or in combination with a solvent and/or a vegetable oil. The amount of surfactant used in the present invention ranges from about 15% to about 95% by weight Surfactants for use in the present invention are pharmaceutically acceptable and include, for example, complex esters or ester-ethers prepared from hexahydric alcohols, alkylene oxides and fatty acids. Surfactants which exist in the liquid state at temperatures at or less than formulation temperature (generally, about 80xc2x0 C. or less, more preferbly about 50-60xc2x0) are preferred because they can also function as co-solvents or co-solubilizers in the present compositions. Exemplary surfactants include Span(trademark) surfactants and Tween(trademark) (polysorbate) surfactants, which are well-known in the art for use as stabilizers, surfactants, emulsifiers and thickeners in foods, cosmetics and medical products, among others. Preferred surfactants are those which are in a liquid state during formulation such that the surfactant may also function as a solubilizer (i.e., it has solvent-like properties). A mixture of surfactants, including a mixture of Span(trademark) and Tween(trademark) surfactants, most preferably, Span(trademark) 80 and Tween(trademark) 80, is preferred for use in the present invention.
The Span(trademark) surfactants are partial esters of common fatty acids, such as lauric acid, palmitic acid, stearic acid and oleic acids and hexitol anhydrides such as hexitans and hexides, derived from sorbitol (see below). In the case of Span 20, the sorbitan fatty ester is based upon laurate ester. In the case of Span 60, the ester is based upon stearate ester and in the case of Span 80, the ester is based upon oleic ester. The hydrophilic character of the Span(trademark) surfactants is supplied by free hydroxyl and oxyethylene groups, while the lipophilic character is provided by the long chain fatty groups. The Span(trademark) surfactants tend to be oil soluble and dispersible or insoluble in water. However, these surfactants work in tandem with the more water soluble polyhydric alcohol to provide a soluble ubiquinol for soft gel formulations according to the present invention. The use of Span 80 in formulating compositions according to the present invention is preferred. 
The Tween(trademark) or polysorbate type surfactants are oleate esters of sorbitol and its anhydrides copolymerized with a number of moles of ethylene oxide per mole of sorbitol and sorbitol anhydride. The Tween(trademark) or polysorbate type surfactants are derived from Span(trademark) materials by polymerizing polyoxyethylene grouops onto the nonesterified alcohols. The Tween(trademark) surfactants are soluble or well dispersible in water. Preferred Tween(trademark) surfactants include a sorbitan mono-9-octadecenoate poly(oxy-1,2-etheandiyl) derivative otherwise known as Tween(trademark) 80 or Polysorbate 80. 
The term xe2x80x9ctriglyceridesxe2x80x9d or xe2x80x9cvegetable oilxe2x80x9d is used throughout the specification to describe an additive in compositions according to the present invention which may serve as a solubilizer or a compatibilizer. This term is used as it is used by those of ordinary skill in the art, wherein fatty acids are esterifed at the free hydroxyl positions of glycerine, producing triglycerides, which are also the primary component of vegetable oils. Preferred triglycerides for use in the present compositions include vegetable oils including xe2x80x9cmedium chain triglyceridesxe2x80x9d, which are tri-fatty esters of glycerol wherein the chain length of the fatty acids range from about 10-18 carbon units. These triglycerides are used as solubilizers, diluents and excipients, to compatabilize the formulations and promote uniformity.
Vegetable oils for use in the present invention may include, for example, tri-glycerides which may be natural or synthetic (derived from esterification of glycerol and at least one organic acid, saturated or unsaturated, such as for example, such as butyric, caproic, palmitic, stearic, oleic, linoleic or linolenic acids, among numerous others, preferably a fatty organic acid, comprising between 8 and 26 carbon atoms). Glyceride esters for use in the present invention include vegetable oils derived chiefly from vegetables, seeds or nuts and include, for example, soybean, sunflower, safflower and cottonseed oil; non-drying oils, for example castor and coconut oil; and other oils, such as, for example palm oil. Hydrogenated vegetable oils also may be used in the present invention. Animal oils are also contemplated for use as glyceride esters and include, for example, fats such as tallow, lard and stearin and liquid fats, such as fish oils, fish-liver oils and other animal oils, including sperm oil, among numerous others. In addition, a number of other oils may be used, including C12 to C30 (or higher) fatty esters (other than the glyceride esters, which are described above) or any other pharmaceutically acceptable triglyceride.
Phosphoglycerides, generally related to triglycerides in that they contain two fatty acid residues and a phosphate ester (generally, a diester) group off of the three hydroxyl groups of glycerine may also be added, alone or in combination with the triglycerides to help compatabilize or solubilize the. The phosphoglyerides may be added for their intrinsic dietary supplement value (for building muscle and nerve tissue, among other functions). These compounds may be included in compositions according to the present invention in amounts ranging from about 0.25% to about 60% by weight, preferably about 0.5% to about 35% by weight.
The term xe2x80x9cstoragexe2x80x9d is used to describe compositions according to the present invention whereby the amount of ubiquinol in a composition after a storage period is at least about 90% by weight the total amount of ubiquinones (which includes ubiquinol and ubiquinone or coenzyme Q10) within the composition. A storage period for purposes of the present invention is at least about 30 days (about 1 month), more preferably at least about 2 months, even more preferably at least about 6 months and even more preferably at least about 1 year.
The term xe2x80x9cpatientxe2x80x9d or xe2x80x9csubjectxe2x80x9d is used throughout the specification to describe an animal, in most instances a human, to whom administration of the compositions according to the present invention is provided.
The term xe2x80x9ceffective amountxe2x80x9d is used throughout the specification to describe concentrations or amounts of compounds according to the present invention which may be used to produce a favorable result, whether that result relates to a composition""s therapeutic or physiological effect or its ability to function as a reducing agent to convert ubiquinone to ubiquinol during manufacturing or to prevent and/or limit the change in or oxidation of the ubiquinol in compositions according to the present invention.
The term xe2x80x9chydrosolublexe2x80x9d is used throughout the specification to describe preferred compositions according to the present invention which are encapsulated in a soft gelatin capsule for oral administration to a patient or subject. The term hydrosoluble is used to indicate the fact that the contents of the soft gelatin capsule are in a form which provides effective, rapid dissolution of the contents of the gelatin capsule in the gastric juices after the gelatin capsule dissolves in the patient""s gastrointestinal tract.
The term xe2x80x9celevated temperaturexe2x80x9d is used throughout the specification to describe a temperature above ambient temperature and generally within a range of about 40xc2x0 C. to about 80xc2x0 C., prerably about 45-50xc2x0 C. to about 55-60xc2x0 C.
The term xe2x80x9csubstantially ubiquinone-freexe2x80x9d is used throughout the specification to describe a composition which contains ubiquinol and little or no ubiquinone. A substantially ubiquinone-free composition according to the present invention is a composition which contains ubiquinol and ubiquinone in a ratio no less than 9:1, preferably no less than 19:1, even more preferably no less than 99:1. In certain preferred embodiments according to the present invention which are xe2x80x9cubiquionone-freexe2x80x9d, virtually no ubiquinone can be found in the ubiquinol used.
The present invention is directed to a composition comprising an effective amount of ubiquinol in combination with a reducing agent in an amount effective to substantially prevent oxidation of ubiquinol to ubiquinone and at least one surfactant or a vegetable oil (triglyceride), in an amount effective to solubilize the ubiquinol and said reducing agent, preferably in a hydrosoluble form. The composition is then formulated in oral dosage form, preferably in a soft gelatin.
In the present invention, the surfactant, where used, comprises about 5% to about 95% by weight of the composition, more preferably about 25% to about 80% by weight, even more preferably about 35% to about 75% by weight. The surfactant for use in the present invention is preferably a Tween(trademark) surfactant or a Span(trademark) surfactant, preferably a mixture of a Tween(trademark) surfactant and a Span(trademark) Surfactant in a weight ratio range of about 30:1 to 2:1, more preferably about 15:1 to about 5:1, even more preferably about 13:1 to about 5:1. Preferably, a mixture of Tween(trademark) 80 and Span(trademark) 80. While these weight ratios will serve to guide the relative amount and ratio of Tween(trademark) surfactant Span(trademark) Surfactant to be included in compositions according to the present invention, one of ordinary skill will be able to readily adjust this ratio to accommodate the ubiquinol and the reducing agent in a compatible formula recognizing that the Span(trademark) surfactants tend to be more oil soluble and the Tween(trademark) surfactants tend to be more water soluble or dispersible.
The amount of triglyceride or vegetable oil which optionally may be used in the present invention may range from about 5% to about 99%, more preferably about 10% to about 85%, even more preferably about 35% to about 80%. The amount of triglyceride included in compositions according to the present invention will depend upon the desired characteristics which are contributed by the triglyceride to the final composition. For example, where the triglyceride is to be used in an amount effective to solubilize the ubiquinol and lipid soluble reducing agent, the amount of triglyceride utilized may be relatively high within the proposed range, because there may be no need to include one or more surfactants and/or solvents according to the present invention. However, surfactants and/or solvents may optionally be added to such formulations. Where surfactants and optionally, solvents are added to the compositions according to the present invention, the amount of triglyceride which may be added to the composition may vary at the lower end of the range as set forth above. Phosphoglycerides may also be added to enhance the effect of the triglycerides in solubilizing and/or compatabilizing the ubiquinol and/or the reducing agent. These phosphoglycerides may also be added for their benefit as dietary supplements.
Compositions according to the present invention are preferably formulated in oral dosage form, even more preferably in soft gelatin capsules as the oral dosage form. The gelatin capsule is taken by the subject orally. It is an unexpected result that the ubiquinol from the soft gelatin oral dosage form results in a significantly enhanced bioavailability of ubiquinol (which is in equilibrium with ubiquinone within the patient) compared to similar compositions which contain ubiquinone alone.
Although ubiquinol can be produced as a first step and then added to the other components in making oral dosage forms according to the present invention, the preferred method is to provide for the in situ preparation of ubiquinol from the less expensive and commercially available ubiquinone. In a preferred method of making compositions according to the present invention from coenzyme Q as the starting material, the components other than the coenzyme Q and, in certain cases, the reducing agent are added together at elevated temperature (generally, at a temperature of about 45-80xc2x0 C., preferably at a temperature of about 50-60xc2x0 C.) until the components are thoroughly mixed. At the point of thorough mixing at elevated temperature, the components are in a liquid state. Subsequent to mixing of the components, coenzyme Q10 is added to the mixture at elevated temperature as described above and throughly mixed into the liquid components for a sufficient period. If the mixture to which the coenzyme Q is added contains an effective concentration of reducing agent, coenzyme Q will be converted to ubiquinol and the mixture can be used to provide oral dosage forms, preferably hard or soft gelatin capsules, even more preferably soft gelatin capsules. In preferred embodiments, after the coenzyme Q10 is added, a reducing agent is thereafter added in an amount effective to convert the coenzyme Q to ubiquinol or alternatively, in an amount which not only is effective to convert coenzyme Q to ubiquinol, but also effective to maintain ubiquinol in its reduced state.
The solubilized composition containing ubiquino, a reducing agent and a surfactant, a vegetable oil or both, in its preferred liquid form is water-free and therefore, suitable for use in oral dosage form, preferably, gelatin capsules, which are prepared by conventional means as those skilled in the art would readily recognize. In preferred embodiments according to the present invention soft gelatin capsules are used, although two-piece hard gelatin capsules may be used (especially where the liquid composition at elevated temperature solidifies at room temperature). The gelatin capsules are generally tasteless, easy to swallow and they readily dissolve in the gastric juices of the digestive tract. Alternatively, the compositions according to the present invention may be provided in tablet form by adsorbing the composition onto a suitable solid carrier or excipient. The compositions according to the present invention can also be provided in a microencapsulated free flowing form. Enteric coated capsules or tablets are also contemplated by the present invention in order to enhance delivery of ubiquinol from the upper gastrointestinal tract (primarily, the duodenum where most of the absorption occurs). One of ordinary skill using standard pharmaceutical formulation and packaging practices will be able to readily prepare any one or more of the oral dosage forms according to the present invention.
Having generally described the invention, reference is now made to the following examples which are intended to illustrate preferred embodiments and comparisons. The included examples are not to be construed as limiting the scope of this invention as is more broadly set forth above and in the appended claims.